Ossë is a fictional character in the works of J. R. R. Tolkien. He is introduced in The Silmarillion as an angelic being known as a Maia, associated with Ulmo, one of the Valar.
A spirit of the sea in the service of Ulmo, Ossë guarded the waters around Middle-earth. He was married to Uinen, and he was a friend of Círdan the Shipwright. During the Years of the Trees, he briefly entered into the service of Melkor and began causing wanton storms which made traveling by sea particularly unsafe. He was persuaded to stop by Uinen, but his taste for storms did not quite disappear.
Ossë was a friend of the Sindar, and was valued as high as the Valar by them. This relationship started before the coming of the Sindar to Valinor, while they dwelled on shores of Middle-earth, waiting for their leader. It was against Ossë's will that they ever go to Valinor.
In older versions of The Silmarillion, Ossë is a Vala in his own right, and often opposed a Maia of Ulmo.